U.S. patent application number 15/666687 was filed with the patent office on 2018-02-08 for gypsum panels, mats therefor, and methods.
This patent application is currently assigned to Georgia-Pacific Gypsum LLC. The applicant listed for this patent is Georgia-Pacific Gypsum LLC. Invention is credited to Rochelle F. Bradford, Yi-Hsien Harry Teng.
Application Number | 20180038101 15/666687 |
Document ID | / |
Family ID | 61068914 |
Filed Date | 2018-02-08 |
United States Patent
Application |
20180038101 |
Kind Code |
A1 |
Teng; Yi-Hsien Harry ; et
al. |
February 8, 2018 |
GYPSUM PANELS, MATS THEREFOR, AND METHODS
Abstract
Methods of making gypsum panels, fiberglass mats, and associated
gypsum panels and building sheathing systems are provided. In one
aspect, a method of making a gypsum panel includes depositing an
aqueous liquid containing a wetting agent onto a fiberglass mat,
such that the aqueous liquid penetrates an entire thickness of the
fiberglass mat, and depositing a gypsum slurry onto the fiberglass
mat onto which the aqueous liquid has been deposited, such that the
gypsum slurry penetrates at least a portion of the fiberglass mat.
In another aspect, a method of making a gypsum panel includes
depositing an aqueous liquid containing a wetting agent onto a
fiberglass mat, and depositing a gypsum slurry onto the fiberglass
mat onto which the aqueous liquid has been deposited, prior to
drying of the aqueous liquid, such that the gypsum slurry
penetrates at least a portion of the fiberglass mat.
Inventors: |
Teng; Yi-Hsien Harry;
(Suwanee, GA) ; Bradford; Rochelle F.; (Decatur,
GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Georgia-Pacific Gypsum LLC |
Atlanta |
GA |
US |
|
|
Assignee: |
Georgia-Pacific Gypsum LLC
Atlanta
GA
|
Family ID: |
61068914 |
Appl. No.: |
15/666687 |
Filed: |
August 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62370671 |
Aug 3, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C04B 32/02 20130101;
C04B 2103/406 20130101; C04B 14/42 20130101; C04B 32/02 20130101;
C04B 32/02 20130101; B05D 2203/35 20130101; C03C 25/1095 20130101;
B05D 3/104 20130101; C04B 24/42 20130101; B05D 1/36 20130101; C04B
2111/0062 20130101; B05D 1/28 20130101; C04B 32/02 20130101; C04B
28/14 20130101; D06M 13/513 20130101; B05D 7/24 20130101; B05D
2203/30 20130101; B05D 3/002 20130101; D06M 13/11 20130101; B05D
7/52 20130101; C03C 13/00 20130101; E04C 2/043 20130101; B32B 13/14
20130101; C04B 28/14 20130101; C03C 2213/00 20130101; B05D 1/305
20130101; C03C 25/54 20130101; C04B 28/14 20130101; C04B 2111/00629
20130101; B05D 2401/20 20130101; B05D 1/02 20130101; D06M 11/83
20130101 |
International
Class: |
E04C 2/04 20060101
E04C002/04; C04B 28/14 20060101 C04B028/14; D06M 13/513 20060101
D06M013/513; D06M 11/83 20060101 D06M011/83; D06M 13/11 20060101
D06M013/11; B05D 1/02 20060101 B05D001/02; C03C 13/00 20060101
C03C013/00 |
Claims
1. A method of making a gypsum panel, comprising: depositing an
aqueous liquid comprising a wetting agent onto a first surface of a
first fiberglass mat, such that the aqueous liquid penetrates an
entire thickness of the fiberglass mat; depositing a gypsum slurry
onto the first surface of the first fiberglass mat onto which the
aqueous liquid has been deposited, such that the gypsum slurry
penetrates at least a portion of the first fiberglass mat; and
allowing the gypsum slurry to set to form a gypsum core.
2. The method of claim 1, wherein the wetting agent is a
surfactant.
3. The method of claim 2, wherein the surfactant is selected from a
group consisting of multifunctional agents based on acetylenic
chemistry, ethoxylated low-foam agents, siloxane-based surfactants,
and nonionic superwetting and coalescing surfactants.
4. The method of claim 2, wherein the surfactant is present in the
aqueous liquid in an amount of about 0.05 percent to about 1
percent, by weight of the liquid.
5. The method of claim 2, wherein the surfactant has a boiling
point of 200.degree. C. or lower.
6. The method of claim 1, wherein the wetting agent has a wet
surface tension of about 50 dyne/cm or less.
7. The method of claim 1, wherein the wetting agent is deposited
onto the first fiberglass mat in an amount of about 0.01 lb/1,000
ft.sup.2 to about 10 lb/1,000 ft.sup.2.
8. The method of claim 1, wherein depositing the aqueous liquid
comprises spraying, roll application, wire rod application,
brushing, rubbing, knife coating, or curtain coating.
9. The method of claim 1, wherein gypsum from the gypsum core
penetrates the first fiberglass mat such that voids in the first
fiberglass mat are substantially eliminated.
10. The method of claim 1, further comprising applying a continuous
barrier coating to a second surface of the first fiberglass mat
opposite the gypsum core, such that the entire thickness of the
first fiberglass mat penetrated by the aqueous liquid is a
thickness from the first surface of the first fiberglass mat to the
continuous barrier coating.
11. The method of claim 1, wherein the gypsum slurry is deposited
onto the fiberglass mat prior to drying of the aqueous liquid.
12. The method of claim 1, wherein the aqueous liquid is free of
any polymer or inorganic binders.
13. A gypsum panel, comprising: a gypsum core having a first
surface and a second surface opposite the first surface; a first
fiberglass mat having a first surface associated with the first
surface of the gypsum core, such that gypsum of the gypsum core
penetrates at least a portion of the first fiberglass mat; and a
wetting agent deposited across an entire thickness of the
fiberglass mat.
14. The gypsum panel of claim 13, wherein the wetting agent is a
surfactant.
15. The gypsum panel of claim 14, wherein the surfactant is
selected from a group consisting of multifunctional agents based on
acetylenic chemistry, ethoxylated low-foam agents, siloxane-based
surfactants, and nonionic superwetting and coalescing
surfactants.
16. The gypsum panel of claim 14, wherein the surfactant has a
boiling point of 200.degree. C. or lower.
17. The gypsum panel of claim 13, wherein the wetting agent is
deposited across the first fiberglass mat in an amount of about
0.01 lb/1,000 ft.sup.2 to about 10 lb/1,000 ft.sup.2.
18. The gypsum panel of claim 13, further comprising a continuous
barrier coating on a second surface of the first fiberglass mat
opposite the first surface, wherein the entire thickness of the
first fiberglass mat across which the wetting agent is deposited is
a thickness from the first surface of the first fiberglass mat to
the continuous barrier coating.
19. The gypsum panel of claim 13, wherein gypsum from the gypsum
core penetrates the first fiberglass mat such that voids in the
first fiberglass mat are substantially eliminated.
20. The gypsum panel of claim 13, further comprising a second
fiberglass mat associated with the second surface of the gypsum
core.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority benefit of U.S. Provisional
Application No. 62/370,671, filed Aug. 3, 2016, which is
incorporated by reference herein.
FIELD
[0002] The present invention relates generally to the field of
panels for use in building construction, and more particularly to
gypsum panels and methods of making gypsum panels.
BACKGROUND
[0003] Typical building panels, or building sheathing, include a
core material, such as gypsum, and a mat facer, such as a
fiberglass mat facer. During manufacturing, the gypsum core
material is traditionally applied as a slurry to a surface of the
mat facer and allowed to set, such that the mat facer and gypsum
core are adhered at the interface. Often, panels surfer from poor
slurry infiltration at the mat facer, resulting in inadequate mat
adhesion to the core material and decreased performance.
[0004] For example, poor slurry infiltration at the mat facer may
lead to increased porosity of the panel, resulting in increased
water penetration and decreased weathering performance. Thus, such
panels typically do not meet building code requirements for air and
water penetration. Indeed, many modern building codes require the
use of barriers in construction to protect the building from air
and water penetration. For example, building codes in eastern
Canada and the northeastern United States now require air barriers
to be used in all construction. Moreover, the existing
International Building Code/International Residential Code
(IBC/IRC) requires the use of a water resistive air barrier for all
new construction. Common water-resistive air barriers are formed
from a variety of materials and structures and applied to the
surface of sheathing panels (e.g., gypsum panels, oriented strand
board (OSB) panels).
[0005] Traditionally, three types of water-resistive air barriers
may be used to meet building codes. First, fabric-type membranes,
or "wraps," may be used to cover the surface of building sheathing
panels. However, these fabric wraps are typically unable to
withstand wind conditions, suffer from drooping, and are difficult
to install at heights. Moreover, the standard method of attaching
such fabric membranes to sheathing panels is stapling, which
compromises the effectiveness of the membrane as an air or water
barrier. Second, a liquid coating water resistive air barrier
membrane may be applied to sheathing panels. However, these liquid
coatings must be applied in the field by qualified contractors,
which is time intensive and costly. Moreover, although liquid
coatings serve as effective an water barrier, they provide low
water vapor permeance, which affects the wall's ability to dry
should it get wet during service (e.g., around window penetrations,
flashing). Third, self-adhered, or "peel and stick," water
resistive air barrier membranes may be applied to sheathing panels.
However, these self-adhered membranes are generally not permeable
and therefore are not an option in many projects, because the
architect or engineer must account for this impermeability in
designing the building, to prevent the potential for moisture being
trapped inside the wall cavity. Furthermore, self-adhered membranes
require the sheathing panels to be dry and often primed prior to
application, which significantly slows down the construction
process.
[0006] Accordingly, it would be desirable to provide panels having
enhanced mat-to-core adhesion and/or panel material penetration
into the mat, to achieve improved water-resistive and air-barrier
properties.
SUMMARY
[0007] In one aspect, methods of making gypsum panels are provided,
including depositing an aqueous liquid containing a wetting agent
onto a first surface of a first fiberglass mat, such that the
aqueous liquid penetrates an entire thickness of the fiberglass
mat, depositing a gypsum slurry onto the first surface of the first
fiberglass mat onto which the aqueous liquid has been deposited,
such that the gypsum slurry penetrates at least a portion of the
first fiberglass mat, and allowing the gypsum slurry to set to form
a gypsum core.
[0008] In another aspect, methods of making a gypsum panel are
provided, including depositing an aqueous liquid comprising a
wetting agent onto a first surface of a first fiberglass mat,
depositing a gypsum slurry onto the first surface of the first
fiberglass mat onto which the aqueous liquid has been deposited,
prior to drying of the aqueous liquid, such that the gypsum slurry
penetrates at least a portion of the first fiberglass mat, and
allowing the gypsum slurry to set to form a gypsum core.
[0009] In yet another aspect a fiberglass mat is provided,
including a fiberglass mat having a first surface and a second
surface opposite the first surface, and a wetting agent deposited
across an entire thickness of the fiberglass mat.
[0010] In still yet another embodiment, a gypsum panel is provided,
including a gypsum core having a first surface and a second surface
opposite the first surface, a first fiberglass mat having a first
surface associated with the first surface of the gypsum core, such
that gypsum of the gypsum core penetrates at least a portion of the
first fiberglass mat, and a wetting agent deposited across an
entire thickness of the fiberglass mat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Referring now to the drawings, which are meant to be
exemplary and not limiting, and wherein like elements are numbered
alike. The detailed description is set forth with reference to the
accompanying drawings illustrating examples of the disclosure, in
which use of the same reference numerals indicates similar or
identical items. Certain embodiments of the present disclosure may
include elements, components, and/or configurations other than
those illustrated in the drawings, and some of the elements,
components, and/or configurations illustrated in the drawings may
not be present in certain embodiments.
[0012] FIG. 1 is a cross-sectional view of a fiberglass faced
gypsum panel having water-resistive and air-barrier properties.
[0013] FIG. 2 is a cross-sectional view of a fiberglass faced
gypsum panel having water-resistive and air-barrier properties.
[0014] FIG. 3 is a perspective view of a building sheathing system
having water-resistive and air-barrier properties.
DETAILED DESCRIPTION
[0015] Disclosed herein are fiberglass mats and gypsum panels, as
well as methods of making such mats and panels. These panels
provide advantages over commercially available gypsum panels, such
as enhanced mat-to-core adhesion and related properties, reduced
porosity in the mat for reducing water penetration, and/or improved
weathering performance. For example, by maximizing gypsum slurry
penetration into the side of the fiberglass mat receiving gypsum,
the movement of water under the mat coating within the glass mat of
the finished panel when exposed to bulk water head pressures may be
substantially and adequately reduced, without significantly
altering the water vapor transmission rate (i.e., the ability to
dry) of the finished panel. Thus, the gypsum panels disclosed
herein may have one or more improved water-resistive and/or
air-barrier properties. As such, these panels and systems of
multiple panels further provide advantages over commercially
available water-resistive air barriers that are attached to
traditional gypsum sheathing (e.g., mechanically attached flexible
sheet, self-adhered sheets, fluid-applied membranes, spray foams),
as well as over wood-based (e.g., OSB) panels, which do not display
the fire resistance properties of gypsum panels.
[0016] As used herein, the term "water-resistive barrier" refers to
the ability of a panel or system to resist liquid bulk water from
penetrating, leaking, or seeping past the sheathing and into the
surrounding wall components while also providing a water vapor
transmission rate, or permeance, that is high enough to allow any
moisture that does develop in the wall to dry. Combined with
flashing around openings, such water-resistive barriers may create
a shingled effect to direct water away from the sheathing and
surrounding wall components. As used herein, the term "air barrier"
refers to the ability of a panel or system to resist the movement
of air into (infiltration) and out of (exfiltration) conditioned
spaces, to create a more energy efficient structure. As used
herein, the term "water-resistive air barrier" refers to the
ability of a panel or system to display both water-resistive
barrier and air barrier properties.
[0017] Gypsum sheathing panels or boards may contain a set gypsum
core sandwiched between two fibrous glass mats, one or both of
which may be coated. The coating may be a continuous barrier
coating. As used herein, the term "continuous barrier coating"
refers to a coating material that is substantially uninterrupted
over the surface of the fibrous mat. The continuous barrier coating
may be any suitable coating material known to those of ordinary
skill in the art. For example, the coating may include a polymer or
resin based binder material along with one or more inorganic
fillers. The continuous barrier coating may be applied on a surface
of the fiberglass mat and penetrates some portion of the thickness
thereof. For example, the continuous barrier coating may penetrate
from about 5 percent to about 60 percent of the thickness of a
typical fiberglass mat (e.g., about 0.04 mm to about 0.4 mm of a
mat having a thickness of about 0.4 mm to about 1.0 mm). For
example, a coating may penetrate from about 20 percent to about 50
percent of the thickness of a typical fiberglass mat (e.g., about
0.1 mm to about 0.3 mm of a mat having a thickness of about 0.5 mm
to about 0.8 mm).
[0018] During manufacturing, a gypsum slurry may be deposited on
the uncoated surface of the fiberglass mat and set to form a gypsum
core of the panel. The gypsum slurry may penetrate some remaining
fibrous portion of the thickness of the fiberglass mat (i.e., some
portion of the fiberglass mat that is not already penetrated by the
coating) and provide a mechanical bond for the panel. The gypsum
slurry may be provided in one or more layers, having the same or
different compositions, including one or more slate coat layers. As
used herein, the term "slate coat" refers to a gypsum slurry having
a higher wet density than the remainder of the gypsum slurry that
forms the gypsum core.
[0019] Traditional gypsum sheathing panels do not consistently pass
industry standard bulk water holdout tests and therefore are
typically covered with commercially available water-resistive air
barriers (e.g., mechanically attached flexible sheets, self-adhered
sheets, fluid-applied membranes or coatings, sprayed foams). It has
been determined that water leaks in these traditional sheathing
panels are formed not only because the seams and openings are not
treated, but also because water under pressure is able to penetrate
though pin holes in the coating on the fiberglass mat surface and
travel through the glass mat along small air pockets or channels
underneath the coating and along the top of the set gypsum core.
This phenomenon is especially noteworthy at or near the edges of
the gypsum panel, where open pockets at the gypsum core-glass mat
interface are more numerous and voluminous. These air pockets, if
interconnected, allow water to travel under the glass mat coating,
resulting in leaks under treated seams, openings, and
fasteners.
[0020] Increasing the thickness of the coating material on the
fiberglass mat has been found ineffective at providing the desired
water-resistive air barrier, because the extra coating weight
results in a greatly reduced water vapor transmission rate and less
potential for drying wet walls in service. Higher coating weights
also increase manufacturing costs and reduce the flexibility of the
coated fiberglass mat, making it prone to cracking at the
edges.
[0021] As such, the present disclosure is directed to providing
gypsum panels and sheathing systems in which such air pockets or
voids are substantially eliminated, so that the panels display the
desired water-resistive and air barrier properties independent of
externally applied barrier products. Such improved sheathing panels
may be combined with seaming components (i.e., components that
treat the joints, or seams, between panels) to greatly reduce the
cost, time, and complexity of installation of a water-resistive air
barrier that provides the desired resistance to bulk water without
affecting the water vapor transmission rate of the panel.
[0022] While this disclosure is generally directed to gypsum
panels, it should be understood that other cementitious panel core
materials are also intended to fall within the scope of the present
disclosure. For example, cementitious panel core materials such as
those including magnesium oxide or aluminosilicate may be
substituted for the gypsum of the embodiments disclosed herein, to
achieve similar results.
[0023] Moreover, while embodiments of the present disclosure are
described generally with reference to fiberglass mats, it should be
understood that other mat materials, including other fibrous mat
materials, may also be used in the present panels. For example,
paper mat facers known in the art may be used. In certain
embodiments, the nonwoven fibrous mat is formed of fiber material
that is capable of forming a strong bond with the material of the
building panel core through a mechanical-like interlocking between
the interstices of the fibrous mat and portions of the core
material. Examples of fiber materials for use in the nonwoven mats
include mineral-type materials such as glass fibers, synthetic
resin fibers, and mixtures or blends thereof. Both chopped strands
and continuous strands may be used.
[0024] Various embodiments of this disclosure are for purposes of
illustration only. Parameters of different steps, components, and
features of the embodiments are described separately, but may be
combined consistently with this description of claims, to enable
other embodiments as well to be understood by those skilled in the
art.
[0025] Panels and Systems
[0026] In certain embodiments, as shown in FIG. 1, a gypsum panel
100 includes a gypsum core 101 having a first surface and a second
opposed surface, and a first fiberglass mat 104 associated with the
first surface of the gypsum core 101, such that gypsum from the
gypsum core penetrates at least a portion of the first fiberglass
mat 104. The various layers are illustrated as separate layers in
the figures for ease of illustration; however, it should be
understood that overlap of these materials may occur at their
interfaces.
[0027] In some embodiments, gypsum crystals of the gypsum core 101
penetrate a remaining portion of the first fiberglass mat 104 such
that voids in the first fiberglass mat 104 are substantially
eliminated and the water resistance of the panel 100 is further
enhanced. For example, in one embodiment, the first fiberglass mat
104 has a continuous barrier coating 106 on a surface opposite the
gypsum core 101, the continuous barrier coating 106 penetrating a
portion of the first fiberglass mat 104, to define the remaining
portion of the first fiberglass mat 104. That is, gypsum crystals
of the gypsum core 101 penetrate a remaining fibrous portion of the
first fiberglass mat 104 such that voids in the first fiberglass
mat 104 are substantially eliminated.
[0028] As used herein the phrase "such that voids in the fiberglass
mat are substantially eliminated" and similar phrases refer to the
gypsum slurry (e.g., slate coat) filling all or nearly all of the
interstitial volume of the fiberglass mat that is not filled by the
coating material. In certain embodiments, gypsum from the gypsum
core fills at least 95 percent of the available interstitial volume
of the coated fiberglass mat. In some embodiments, the gypsum core
fills at least 98 percent of the available interstitial volume of
the coated fiberglass mat. In further embodiments, the gypsum core
fills at least 99 percent of the available interstitial volume of
the coated fiberglass mat. Such panels, in which the gypsum
penetrates the mat such that the voids in the mat are substantially
eliminated, may be manufactured via a variety of methods, as
discussed in more detail herein. Specifically, the first fiberglass
mat may be treated with an aqueous liquid containing a wetting
agent prior to deposition of the gypsum slurry thereon. The wetting
agent promotes penetration of the gypsum into the fiberglass mat,
aiding in reducing voids in the fiberglass mat. Moreover, the
wetting agent provides relatively faster board drying, enhanced
mat-to-core adhesion, water repellence, and membrane peel and scrub
resistance.
[0029] In certain embodiments, a second surface 107 of the panel
100 formed by the first fiberglass mat 104 displays a water contact
angle of at least 90 degrees, a Cobb surface water absorption
measurement of 2 grams or less, or both. In some embodiments, the
second surface 107 of the panel displays a Cobb surface water
absorption measurement of 1 gram or less. Thus, the panels
described herein may display superior surface water resistance or
wettability properties. As used herein, the phrase "water contact
angle" refers to the contact angle formed by a liquid in contact
with the surface.
[0030] In some embodiments, in addition to the aqueous liquid
containing the wetting agent being applied to the fibrous mat to
aid in gypsum slurry penetration, further techniques are
incorporated into the gypsum panel manufacturing process to enhance
gypsum penetration into the fibrous mat and further reduce voids in
the mat. For example, such additional techniques may include those
disclosed in U.S. patent application Ser. Nos. 15/014,793,
15/014,821, and 15/014,922, each of which was filed on Feb. 3, 2016
and is entitled "Gypsum Panels, Systems, and Methods".
[0031] Aqueous Liquid Containing Wetting Agent
[0032] The aqueous liquid containing the wetting agent may be of
any suitable chemistry, including solutions, suspensions, and
emulsions of water and the wetting agent, along with any additional
components as discussed herein.
[0033] In certain embodiments, the wetting agent is deposited
across an entire thickness of the fiberglass mat. That is, the
wetting agent is deposited across the entire thickness of the mat
from the first (internal) surface of the fiberglass mat to the
second opposed surface of the fiberglass mat, or to any continuous
barrier coating that is present on the second surface of the
fiberglass mat. As used herein, the phrases "penetrates the
thickness," "is deposited across," and similar phrases, when used
to described the migration of the wetting agent across the fibrous
mat, refer to a wetting out of the surfaces of the fibrous mat, and
do not necessarily mean that the wetting agent fills all open
volume or voids of the mat.
[0034] Suitable wetting agents are discussed in further detail
below.
[0035] Fiberglass Mats
[0036] In certain embodiments, fiberglass mats for use in the
manufacture of sheathing panels are provided herein. For example, a
fiberglass mat may have a first surface and a second surface
opposite the first surface and a wetting agent deposited across an
entire thickness of the fiberglass mat (e.g., across a thickness
form the first surface to the second surface or from the first
surface to any continuous barrier coating that is present on the
second surface), as discussed in further detail herein.
[0037] In certain embodiments, the mat is a nonwoven fiberglass
mat. For example, the glass fibers may have an average diameter of
from about 10 to about 17 microns and an average length of from
about 1/4 inch to about 1 inch. For example, the glass fibers may
have an average diameter of 13 microns (i.e., K fibers) and an
average length of 3/4 inch. In certain embodiments, the non-woven
fiberglass mats have a basis weight of from about 1.5 pounds to
about 3.5 pounds per 100 square feet of the mat. The mats may each
have a thickness of from about 20 mils to about 35 mils. The fibers
may be bonded together to form a unitary mat structure by a
suitable adhesive. For example, the adhesive may be a
urea-formaldehyde resin adhesive, optionally modified with a
thermoplastic extender or cross-linker, such as an acrylic
cross-linker, or an acrylate adhesive resin.
[0038] Continuous Barrier Coating
[0039] As discussed above, the continuous barrier coating on the
external surface of the fiberglass mat may be any suitable coating
known in the art. For example, the coating may include a binder
material and, optionally, a filler. In certain embodiments, the
coating contains filler in an amount from about 75 to about 97
weight percent. For example, the coating may contain filler in an
amount from about 80 to about 95 weight percent. In one embodiment,
the mat coating has a basis weight from about 3 pounds to about 9
pounds of solids per 100 square feet of the fiberglass mat. In one
embodiment, the mat coating has a basis weight from about 2 pounds
to about 8 pounds of solids per 100 square feet of the fiberglass
mat. In certain embodiments, the binder is a polymer material. In
certain embodiments, the coating on the first and/or second
fiberglass mat is a latex acrylic polymer containing at least one
inorganic filler.
[0040] In some embodiments, the binder of the continuous mat
coating is a polymer latex adhesive. For example, the binder may be
styrene-butadiene-rubber (SBR), styrene-butadiene-styrene (SBS),
ethylene-vinyl-chloride (EVCl), poly-vinylidene-chloride (PVdCl)
and poly(vinylidene) copolymers, modified poly-vinyl-chloride
(PVC), poly-vinyl-alcohol (PVOH), ethylene-vinyl-acetate (EVA),
poly-vinyl-acetate (PVA) and polymers and copolymers containing
units of acrylic acid, methacrylic acid, their esters and
derivatives thereof (acrylic-type polymers), such as
styrene-acrylate copolymers.
[0041] In one embodiment, the binder of the continuous mat coating
is a hydrophobic, UV resistant polymer latex adhesive. For example,
the hydrophobic, UV resistant polymer latex binder adhesive may be
based on a (meth)acrylate polymer latex, wherein the (meth)acrylate
polymer is a lower alkyl ester, such as a methyl, ethyl or butyl
ester, of acrylic and/or methacrylic acids, and copolymers of such
esters with minor amounts of other ethylenically unsaturated
copolymerizable monomers (such as styrene) which are known to the
art to be suitable in the preparation of UV resistant (meth)acrylic
polymer latexes.
[0042] In certain embodiments, the continuous barrier coating also
includes water and/or other optional ingredients such as colorants
(e.g., dyes or pigments), transfer agents, thickeners or
rheological control agents, surfactants, ammonia compositions,
defoamers, dispersants, biocides, UV absorbers, and preservatives.
Thickeners may include hydroxyethyl cellulose; hydrophobically
modified ethylene oxide urethane; processed attapulgite, a hydrated
magnesium aluminosilicate; and other thickeners known to those of
ordinary skill in the art. For example, thickeners may include
CELLOSIZE QP-09-L and ACRYSOL RM-2020NPR, commercially available
from Dow Chemical Company (Philadelphia, Pa.); and ATTAGEL 50,
commercially available from BASF Corporation (Florham Park, N.J.).
Surfactants may include sodium polyacrylate dispersants,
ethoxylated nonionic compounds, and other surfactants known to
those of ordinary skill in the art. For example, surfactants may
include HYDROPALAT 44, commercially available from BASF
Corporation; and DYNOL 607, commercially available from Air
Products (Allentown, Pa.). Defoamers may include multi-hydrophobe
blend defoamers and other defoamers known to those of ordinary
skill in the art. For example, defoamers may include FOAMASTER
SA-3, commercially available from BASF Corporation. Ammonia
compositions may include ammonium hydroxide, for example, AQUA
AMMONIA 26 BE, commercially available from Tanner Industries, Inc.
(Southampton, Pa.). Biocides may include broad-spectrum
microbicides that prohibit bacteria and fungi growth,
antimicrobials such as those based on the active
diiodomethyl-ptolylsulfone, and other compounds known to those of
ordinary skill in the art. For example, biocides may include KATHON
LX 1.5%, commercially available from Dow Chemical Company,
POLYPHASE 663, commercially available from Troy Corporation
(Newark, N.J.), and AMICAL Flowable, commercially available from
Dow Chemical Company. Biocides may also act as preservatives. UV
absorbers may include encapsulated hydroxyphenyl-triazine
compositions and other compounds known to those of ordinary skill
in the art, for example, TINUVIN 477DW, commercially available from
BASF Corporation. Transfer agents such as polyvinyl alcohol (PVA)
and other compounds known to those of ordinary skill in the art may
also be included in the coating composition.
[0043] In certain embodiments, a hydrophobic latex or resin
material can be included in the continuous mat coating to further
improve the water repellence and reduce the water infiltration and
enhance bonding between glass mat and gypsum.
[0044] Fillers used in the continuous mat coating may include
inorganic mineral fillers, such as ground limestone (calcium
carbonate), clay, mica, gypsum (calcium sulfate dihydrate),
aluminum trihydrate (ATH), antimony oxide, sodium-potassium alumina
silicates, pyrophyllite, microcrystalline silica, talc (magnesium
silicate), and other fillers known to those of ordinary skill in
the art. In certain embodiments, the filler may inherently contain
a naturally occurring inorganic adhesive binder. For example, the
filler may be limestone containing quicklime (CaO), clay containing
calcium silicate, sand containing calcium silicate, aluminum
trihydrate containing aluminum hydroxide, cementitious fly ash, or
magnesium oxide containing either the sulfate or chloride of
magnesium, or both. In certain embodiments, the filler may include
an inorganic adhesive binder as a constituent, cure by hydration,
and act as a flame suppressant. For example, the filler may be
aluminum trihydrate (ATH), calcium sulfate (gypsum), and the
oxychloride and oxysulfate of magnesium. For example, fillers may
include MINEX 7, commercially available from the Cary Company
(Addison, Ill.); IMSIL A-10, commercially available from the Cary
Company; and TALCRON MP 44-26, commercially available from
Specialty Minerals Inc. (Dillon, Mont.). The filler may be in a
particulate form. For example, the filler may have a particle size
such that at least 95% of the particles pass through a 100 mesh
wire screen.
[0045] Gypsum Core
[0046] In certain embodiments, as shown in FIG. 1, the gypsum core
101 includes two or more gypsum layers 102, 108. For example, the
gypsum core may include various gypsum layers having different
compositions. In some embodiments, the first gypsum layer 102 that
is in contact with the fiberglass mat 104 (i.e., the layer that
forms an interface with the coating material and at least partially
penetrates the remaining fibrous portion of the first fiberglass
mat) is a slate coat layer. In some embodiments, the first gypsum
layer 102 is present in an amount from about 5 percent to about 20
percent, by weight, of the gypsum core 101. The various gypsum
layers are shown as separate layers in the figures for ease of
illustration; however, it should be understood that overlap of
these materials may occur at their interfaces.
[0047] In some embodiments, the slurry that forms the gypsum layer
having an interface with the barrier coating also includes a
wetting agent to facilitate penetration of the slurry into the
fibrous mat. This slurry may form the entire gypsum core or may
form one or more layers of the gypsum core. That is, one or more
layers forming the gypsum core may contain the wetting agent. As
discussed in more detail below, the wetting agent may be any agent
that reduces the surface tension of the slurry. In certain
embodiments, the first gypsum layer includes a wetting agent in an
amount effective to bring a slurry surface tension of the first
gypsum layer to 65 dyne/cm or less. In certain embodiments, the
first gypsum layer includes a wetting agent in an amount effective
to bring a slurry surface tension of the first gypsum layer to 60
dyne/cm or less. In certain embodiments, the first gypsum layer
includes a wetting agent in an amount effective to bring a slurry
surface tension of the first gypsum layer to 55 dyne/cm or less. In
certain embodiments, the first gypsum layer includes a wetting
agent in an amount effective to bring a slurry surface tension of
the first gypsum layer to from about 30 dyne/cm to about 60
dyne/cm. In certain embodiments, the first gypsum layer includes a
wetting agent in an amount effective to bring a slurry surface
tension of the first gypsum layer to from about 40 dyne/cm to about
60 dyne/cm. In certain embodiments, the first gypsum layer includes
a polymer binder or an inorganic binder in an amount of from about
0.5 lb/1000 ft.sup.2 to about 50 lb/1000 ft.sup.2, in the set
gypsum layer. In certain embodiments, the first gypsum layer
includes a polymer binder or an inorganic binder in an amount of
from about 0.5 lb/1000 ft.sup.2 to about 15 lb/1000 ft.sup.2, in
the set gypsum layer.
[0048] In some embodiments, the first gypsum layer has a wet
density of from about 88 pcf to about 98 pcf. In some embodiments,
the first gypsum layer has a wet density of from about 93 pcf to
about 96 pcf.
[0049] In certain embodiments, penetration of the gypsum slurry
into the fibrous mat is further encouraged with a polymer binder
coating or an inorganic binder coating on a surface of the first
fiberglass mat that contacts the gypsum core. In some embodiments,
the mat coating comprises a wetting agent in an amount effective to
bring a wet surface tension of the coating to 60 dyne/cm or less.
In some embodiments, the mat coating comprises a wetting agent in
an amount effective to bring a wet surface tension of the coating
to from about 30 dyne/cm to about 60 dyne/cm. In some embodiments,
the mat coating comprises a wetting agent in an amount effective to
bring a wet surface tension of the coating to from about 40 dyne/cm
to about 60 dyne/cm.
[0050] In certain embodiments, as shown in FIG. 2, a gypsum panel
200 includes two fiberglass mats 204, 212 that are associated with
the gypsum core 201. The second fiberglass mat 212 is present on a
face of the gypsum core 201 opposite the first fiberglass mat 204.
In some embodiments, only the first fiberglass mat 204 has a
continuous barrier coating 206 on a surface thereof. In other
embodiments, both fiberglass mats 204, 212 have a coating 206, 214
on a surface thereof opposite the gypsum core 201. In some
embodiments, the gypsum core 201 includes three gypsum layers 202,
208, 210. One or both of the gypsum layers 202, 210 that are in
contact with the fiberglass mats 204, 212 may be a slate coat
layer. In certain embodiments, one or both of the gypsum layers
202, 210 that are in contact with the fiberglass mats 204, 212 may
be a slate coat layer with hydrophobic characteristics and/or a wet
density of from about 88 pcf to about 98 pcf, or of from about 93
pcf to about 96 pcf.
[0051] The layers of the gypsum core may be similar to gypsum cores
used in other gypsum products, such as gypsum wallboard, dry wall,
gypsum board, gypsum lath, and gypsum sheathing. For example, the
gypsum core may be formed by mixing water with powdered anhydrous
calcium sulfate or calcium sulfate hemihydrate, also known as
calcined gypsum, to form an aqueous gypsum slurry, and thereafter
allowing the slurry mixture to hydrate or set into calcium sulfate
dihydrate, a relatively hard material. In certain embodiments, the
gypsum core includes about 80 weight percent or above of set gypsum
(i.e., fully hydrated calcium sulfate). For example, the gypsum
core may include about 85 weight percent set gypsum. In some
embodiments, the gypsum core includes about 95 weight percent set
gypsum. The gypsum core may also include a variety of additives,
such as accelerators, set retarders, foaming agents, and dispersing
agents.
[0052] In certain embodiments, one or more layers of the gypsum
core also include reinforcing fibers, such as chopped glass fibers.
For example, the gypsum core, or any layer thereof, may include up
to about 0.6 pounds of reinforcing fibers per 100 square feet of
panel. For example, the gypsum core, or a layer thereof, may
include about 0.3 pounds of reinforcing fibers per 100 square feet
of panel. The reinforcing fibers may have a diameter between about
10 and about 17 microns and have a length between about 6.35 and
about 12.7 millimeters.
[0053] The gypsum core, or one or more layers thereof, such as one
or more slate coat layers, may also include an additive that
improves the water-resistant properties of the core. Such additives
may include, for example, poly(vinyl alcohol), optionally including
a minor amount of poly(vinyl acetate); metallic resinates; wax,
asphalt, or mixtures thereof, for example as an emulsion; a mixture
of wax and/or asphalt and cornflower and potassium permanganate;
water insoluble thermoplastic organic materials such as petroleum
and natural asphalt, coal tar, and thermoplastic synthetic resins
such as poly(vinyl acetate), poly(vinyl chloride), and a copolymer
of vinyl acetate and vinyl chloride, and acrylic resins; a mixture
of metal rosin soap, a water soluble alkaline earth metal salt, and
residual fuel oil; a mixture of petroleum wax in the form of an
emulsion and either residual fuel oil, pine tar, or coal tar; a
mixture of residual fuel oil and rosin; aromatic isocyanates and
diisocyanates; organopolysiloxanes; siliconates; wax emulsions,
including paraffin, microcrystalline, polyethylene, and various
co-emulsified wax emulsions; wax asphalt emulsion, each optionally
with potassium sulfate, alkali, or alkaline earth aluminates, and
Portland cement; a wax-asphalt emulsion prepared by adding to a
blend of molten wax and asphalt, an oil-soluble, water-dispersing
emulsifying agent, and admixing the aforementioned with a solution
of case including, as a dispersing agent, an alkali sulfonate of a
polyarylmethylene condensation product. Mixtures of these
water-resistance additives may also be employed. For example, a
mixture of two or more of: poly(vinyl alcohol), siliconates, wax
emulsion, and wax-asphalt emulsion of the aforementioned types, may
be used to improve the water resistance of the gypsum core, or
gypsum slate coat layer(s) thereof.
[0054] The gypsum core, or one or more layers thereof, may also
include one or more additives that enhance the inherent fire
resistance of the gypsum core. Such additives may include chopped
glass fibers, other inorganic fibers, vermiculite, clay, Portland
cement, and other silicates, among others.
[0055] Properties of Gypsum Panels
[0056] In certain embodiments, the panels have a thickness from
about 1/4 inch to about 1 inch. For example, the panels may have a
thickness of from about 1/2 inch to about 5/8 inch.
[0057] By maximizing gypsum slurry penetration into the side of the
fiberglass mat receiving gypsum, at least through the use of an
aqueous liquid containing a wetting agent deposited on the fibrous
mat prior to application of the gypsum slurry thereto, the movement
of water under the mat coating within the glass mat of the finished
panel when exposed to bulk water head pressures may be
substantially and adequately reduced, without significantly
altering the water vapor transmission rate (i.e., the ability to
dry) of the finished panel. Thus, the gypsum panels disclosed
herein may have one or more improved water-resistive barrier
properties.
[0058] In certain embodiments, the gypsum panel passes a
hydrostatic head test against water leakage, as measured by AATCC
127-2008. In addition to hydrostatic head pressure tests, other
similar tests can be used to assess bulk water resistance in the
range of 0.32 inches water (1.67 psf) to 44 inches of water head
pressure (228 psf). This may include but is not limited to other
water head tests (such as ASTM E2140), water ponding tests, cobb
tests (such as ASTM C473, ASTM D3285, ASTM D5795, ASTM D7433, ASTM
D7281), or a chambered test aided by vacuum or negative pressure
differentials. Thus, the gypsum panels described herein may pass
any combination of the foregoing tests.
[0059] In certain embodiments, the gypsum panel has a water vapor
permeance of at least 10 (inch-pound units per ASTM E96 wet cup
method), in the field of the panel (i.e., not at the edge of the
panel). In some embodiments, the gypsum panel has a water vapor
permeance of at least 30 (inch pound units per ASTM E96 wet cup
method), in the field of the panel. In some embodiments, the gypsum
panel has a water vapor permeance of at least 32 (inch pound units
per ASTM E96 wet cup method), in the field of the panel. In certain
embodiments, the gypsum panel displays water vapor transmission
properties as determined by desiccant methods or by other methods
including high and low relative humidity or dynamic pressure
levels.
[0060] In certain embodiments, the gypsum panel displays an air
penetration resistance of 0.02 L/sm.sup.2 at 75 Pa, or less, when
measured according to ASTM E2178. In certain embodiments, the
gypsum panel displays an air penetration resistance of 0.02
L/sm.sup.2 at 300 Pa, or less, when measured according to ASTM
E2178.
[0061] In certain embodiments, the gypsum panel is fire-resistant.
In certain embodiments, the gypsum panel is classified as
noncombustible when tested in accordance with ASTM E136 or CAN/ULC
S114 and complies with ASTM C1177 requirements for glass mat gypsum
substrates designed to be used as exterior sheathing for weather
barriers. In particular, a 5/8 inch panel may have increased fire
resistance over other sheathing substrates, such as cellulosic
based sheathing. In some embodiments, the gypsum panel has a "Type
X" designation, when measured according to ASTM E119. The gypsum
panels may meet "Type X" designation when tested in accordance with
ASTM E119 fire tests for both generic (Generic systems in the
GA-600 Fire Resistance Design Manual) and proprietary building
assembly wall designs. ASTM E119 is designed to test the duration
for which a building assembly can contain a fire and retain
structural integrity under a controlled fire with a standard
time/temperatures curve. In certain embodiments, the gypsum panel
has a level 0 flame spread index and smoke develop index, when
measured according to ASTM E84. For example, when exposed to
surface burning characteristics, per ASTM E 84 or CAN/ULC-S102, the
flame spread index and smoke develop index for the gypsum panel may
be 0.
[0062] Building Sheathing Systems
[0063] Building sheathing systems are also provided herein, and
include at least two of the improved water-resistive air barrier
gypsum panels described herein, including any features, or
combinations of features, of the panels described herein. For
example, the gypsum panels may each include a gypsum core
associated with a first fiberglass mat having a barrier coating,
the coating penetrating a portion of the first fiberglass mat
opposite the gypsum core, wherein gypsum of the gypsum core
penetrates a remaining fibrous portion of the first fiberglass mat
such that voids in the first fiberglass mat are substantially
eliminated.
[0064] In certain embodiments, as shown in FIG. 3, a building
sheathing system includes at least two gypsum panels 300 and a
seaming component 320 configured to provide a seam at an interface
between at least two of the gypsum panels 300.
[0065] In certain embodiments, the seaming component comprises tape
or a bonding material. For example, the seaming component may be a
tape including solvent acrylic adhesives, a tape having a
polyethylene top layer with butyl rubber adhesive, a tape having an
aluminum foil top layer with butyl rubber adhesive, a tape having
an EPDM top layer with butyl rubber adhesive, a tape having a
polyethylene top layer with rubberized asphalt adhesive, or a tape
having an aluminum foil top layer with rubberized asphalt adhesive.
For example, the seaming component may be a bonding material such
as synthetic stucco plasters, cement plasters, synthetic acrylics,
sand filled acrylics, solvent based acrylics, solvent based butyls,
polysulfides, polyurethanes, silicones, silyl modified polymers,
water-based latexes, EVA latexes, or acrylic latexes.
[0066] Thus, the above-described enhanced panels may be installed
with either a tape, liquid polymer, or other suitable material, to
effectively treat areas of potential water and air intrusion, such
as seams, door/window openings, penetrations, roof/wall interfaces,
and wall/foundation interfaces. As such, the building sheathing
panels, when used in combination with a suitable seaming component,
create an effective water-resistive and/or air-barrier
envelope.
[0067] Such building sheathing systems may advantageously pass any
or all ICC-ES tests required for water resistant and air barrier
system performance. For example, the sheathing systems may pass
Sections 4.1, 4.2, 4.3, 4.4, 4.7, and/or 4.8 of the ICC-ES
Acceptance Criteria for water-resistive coatings used as
water-resistive barriers over exterior sheathing (ICC Evaluation
Service Acceptance Criteria 212), dated February 2015. For example,
the sheathing systems may pass Section 4.5 of the ICC-ES Acceptance
Criteria for water-resistive membranes factory bonded to wood-based
structural sheathing, used as water-resistive barriers (ICC
Evaluation Service Acceptance Criteria 310), dated May 2008,
revised June 2013.
[0068] In certain embodiments, the building sheathing system
including at least two gypsum panels and a seaming component
displays no water leaks when measured according ICC Evaluation
Service Acceptance Criteria 212, Section 4. This test uses an 8' by
8' wall assembly built with multiple gypsum panels and having two
vertical joint treatments and one horizontal joint treatment with
seaming component(s) (as described in more detail herein) and
flashing treatment with seaming component(s). The wall is subjected
to 10 positive transverse load cycles of ASTM E2357 (procedure A),
to racking loads of ASTM E72 to obtain a net deflection of 1/8 inch
with hold-downs, and then to restrained environmental conditioning
cycles as described in AC 212 section 4.7.3 for two weeks. Thus, in
some embodiments, the building sheathing system displays no water
leaks when measured according to ICC Evaluation Service Acceptance
Criteria 212, Section 4, after being subjected to the test methods
of ASTM E2357 procedure A, ASTM E72, and restrained environmental
conditioning. The cycled wall is then tested under ASTM E331 water
penetration with a water spray of 5 gal/ft.sup.2-hr and air
pressure differential of 2.86 psf maintained for 15 minutes, and
resulting in no leaks within the field of the panel or cracking of
sheathing or seaming components.
[0069] Thus, in some embodiments, the building sheathing system
displays no water leaks when measured according to the ASTM E331
wall assembly test at an air pressure differential of 2.86 psf,
6.24 psf, or even 8.58 psf. The ASTM E331 test may be a water spray
after a structural test and/or a test including the building
transitions, openings, and penetrations. In addition to ASTM E331,
other suitable tests may be substituted, such as tests using
chambers that spray or flood the exposed side of the wall or are
rotated to receive bulk water and create a negative air pressure
differential on the inside cavity in order to expose leaks. This
may include but is not limited to ASTM E547, ASTM D5957, AAMA 501,
or field testing apparatus such as ASTM E1105. Thus, the building
sheathing systems described herein may pass any combination of the
foregoing tests.
[0070] In certain embodiments, the building sheathing system
displays an air penetration resistance of 0.02 L/sm.sup.2 at 75 Pa,
or less, when measured according to ASTM E2178. In certain
embodiments, the sheathing system displays an air penetration
resistance of 0.02 L/sm.sup.2 at 300 Pa, or less, when measured
according to ASTM E2178.
[0071] In certain embodiments, the building sheathing system
displays an exfiltration and infiltration air leakage rate of less
than 0.04 cfm/ft.sup.2 at 1.57 lbs/ft.sup.2 (75 Pa), when measured
according to the ASTM E2357 air barrier assembly test for both
opaque walls and walls with penetration, when 8' by 8' walls are
prepared using seaming components to seal joints, window openings,
duct penetrations, pipe penetrations, external junction boxes, and
masonry ties. In some embodiments, the ASTM E2357 wall assemblies,
after being is exposed to Q10>0.20 kPa pressure design value
wind loads for sustained, cyclic, and gust loads display an air
leakage infiltration and exfiltration rate of less than 0.04
cfm/ft.sup.2 at 6.27 lbs/ft.sup.2 (300 Pa). In certain embodiments,
the building sheathing system displays an exfiltration and
infiltration air leakage rate of less than 0.02 cfm/ft.sup.2 at
1.57 lbs/ft.sup.2 (75 Pa), when measured according to the ASTM
E2357 air barrier assembly test for both opaque walls and walls
with penetration. In addition to ASTM E2357, other tests may be
used to quantify air leakage in this range, including ASTM E283,
ASTM E2319, ASTM E1424, ASTM E283, ASTM E1424, or similar test
methods. Also, related field testing to test pressure
differentials, in this range, such as ASTM E783 or related blower
door apparatus testing may also be used. Thus, the building
sheathing systems described herein may pass any combination of the
foregoing tests.
[0072] In some embodiments, the system passes a hydrostatic head
test against water leakage, as measured by AATCC 127-2008. In
certain embodiments, the building sheathing system passes AATCC
hydrostatic head test method 127-2008 for a 22-inch head of water
(114 psf water pressure) directly over an interface of at least two
gypsum panels and the seaming component, with no leaks after 5
hours. In addition to hydrostatic head pressure, other similar
tests can be used to assess bulk water resistance in the range of
0.32 inches water (1.67 psf) to 44 inches of water head pressure
(228 psf). This may include but is not limited to other water head
tests (such as ASTM E2140), water ponding test, cobb tests (such as
ASTM C473, ASTM D3285, ASTM D5795, ASTM D7433, ASTM D7281), or a
chambered test aided by vacuum or negative pressure differentials.
Thus, the building sheathing systems described herein may pass any
combination of the foregoing tests.
[0073] In certain embodiments, the system passes AC310-2008, which
tests water-resistive membranes and barriers. In some embodiments,
the system passes AAMA 714 standard for liquid-applied
flashing.
[0074] In certain embodiments, the sheathing system has a water
vapor permeance of at least 10 (inch-pound units per ASTM E96 wet
cup method). In certain embodiments, the sheathing system has a
water vapor permeance of at least 20 (inch-pound units per ASTM E96
wet cup method).
[0075] Accordingly, the presently described systems are especially
effective along the edges of the panel, which are traditionally
more susceptible to leaks when installed in a finished system.
[0076] Thus, in certain embodiments, the sheathing system (i)
passes a hydrostatic head test against water leakage, as measured
by AATCC 127-2008, (ii) displays no water leaks when measured
according to ICC Evaluation Service Acceptance Criteria 212,
Section 4, after being subjected to the test methods of ASTM E2357
procedure A, ASTM E72, and restrained environmental conditioning,
and/or (iii) displays no water leaks when measured according to
ASTM E331 wall assembly test at an air pressure of 2.86 psf, 6.24
psf, or 8.58 psf. Therefore, the sheathing system may display
certain levels of water resistive properties. Additionally, such
sheathing systems may further display desired water vapor
permeance, air penetration resistance, air leakage rate, and fire
resistant properties. These sheathing systems therefore provide a
water resistive air barrier in the absence of any externally
applied barrier product, other than the seaming component. That is,
no mechanically attached flexible barrier sheet material,
self-adhered barrier sheet material, fluid-applied membranes, spray
foam membrane, or other barrier product need be applied to the
external field of the panels to achieve the water-resistive air
barrier properties.
[0077] Thus, in certain embodiments, the sheathing system includes
panels having a gypsum core (one or more layers, optionally
including one or more slate coat layers) and a fiberglass mat
facer, wherein an aqueous liquid containing a wetting agent has
been applied to the fiberglass mat facer during the panel
manufacturing process, which panels display the water-resistive air
barrier properties described herein, independent of any barrier
product (e.g., mechanically attached flexible barrier sheet
material, self-adhered barrier sheet material, fluid-applied
membranes, spray foam membrane) being applied to the external
surface of the panel during building construction.
[0078] Methods
[0079] Methods of making gypsum panels having water-resistive
properties, and fiberglass mats therefor, are also provided. In
certain embodiments, methods of making a fiberglass mat include
depositing an aqueous liquid containing a wetting agent onto a
first surface of a first fiberglass mat. In some embodiments, the
aqueous liquid containing the wetting agent penetrates an entire
thickness of the fiberglass mat. In certain embodiments, methods of
making a gypsum panel include depositing an aqueous liquid
containing a wetting agent onto a first surface of a first
fiberglass mat and depositing a gypsum slurry onto the first
surface of the first fiberglass mat onto which the aqueous liquid
has been deposited such that the gypsum slurry penetrates at least
a portion of the first fiberglass mat, and allowing the gypsum
slurry to set to form a gypsum core. In certain embodiments, the
gypsum slurry is deposited onto the fiberglass mat prior to drying
of the aqueous liquid. That is, the gypsum slurry is deposited
prior to complete evaporation of the water in which the wetting
agent is applied to the fibrous mat. It has been found that
applying the gypsum slurry to the fibrous mat at a time when the
aqueous liquid remains wet aids in enhancing the penetration of the
gypsum slurry into the mat.
[0080] These methods may be used to produce gypsum panels having
any of the features, or combinations of features, described herein.
For example, enhanced penetration of the gypsum into the fiberglass
mat may be achieved by application of the penetration-enhancing
wetting agent to the fibrous mat contacted by the gypsum
slurry.
[0081] Aqueous Liquid Containing Wetting Agent
[0082] The aqueous liquid containing the wetting agent is applied
to the fibrous mat to enhance the penetration of the gypsum slurry
into the remaining voids of the fibrous mat upon application of the
gypsum slurry thereto. As discussed above, in certain embodiments,
the e gypsum slurry is deposited onto the fiberglass mat prior to
drying of the aqueous liquid containing the wetting agent, to
maximize the effect of the wetting agent.
[0083] In certain embodiments, the aqueous liquid is applied to the
fibrous mat such that the wetting agent penetrates an entire
thickness of the mat, as discussed above. The aqueous liquid may be
applied to a mat that has been coated with a continuous barrier
coating on a surface opposite the surface to which the aqueous
liquid containing the wetting agent is applied, or to an uncoated
mat. In some embodiments, the aqueous liquid is applied to the
fibrous mat such that the gypsum slurry applied to the fibrous mat
penetrates the mat such that voids in the mat are substantially
eliminated.
[0084] In certain embodiments, the wetting agent is present in the
aqueous liquid in an amount of from about 0.05 percent to about 1
percent, such as in an amount of from about 0.1 percent to about
0.5 percent, or in an amount of about 0.05 percent to about 0.2
percent, by weight of the liquid components of the aqueous liquid
(i.e., not including any solids present in the aqueous liquid).
[0085] The wetting agent may be any suitable chemical that acts to
lower surface tension. That is, the wetting agent may be any
suitable agent that acts to lower the surface tension of the gypsum
slurry applied to the glass mat. For example, the wetting agent may
have a wet surface tension that is lower than the surface tension
of water. For example, the wetting agent may have a wet surface
tension of about 50 dyne/cm or less. In certain embodiments, the
aqueous liquid contains the wetting agent in an amount effective to
bring a wet surface tension of the solution to 60 dyne/cm or less,
such as from about 40 dyne/cm to about 60 dyne/cm.
[0086] In certain embodiments, the wetting agent is selected from a
group consisting of surfactants, superplasticisers, dispersants,
agents containing surfactants, agents containing superplasticisers,
agents containing dispersants, and combinations thereof.
Specifically, suitable wetting agents may be selected from
non-ionic, anionic, cationic, or zwitterionic compounds, such as
alkyl sulfates, ammonium lauryl sulfate, sodium lauryl sulfate,
alkyl-ether sulfates, sodium laureth sulfate, sodium myreth
sulfate, docusates, dioctyl sodium sulfosuccinate,
perfluorooctanesulfonate, perfluorobutanesulfonate, linear
alkylbenzene sulfonates, alkyl-aryl ether phosphates, alkyl ether
phosphate, alkyl carboxylates, sodium stearate, sodium lauroyl
sarcosinate, carboxylate-based fluorosurfactants,
perfluorononanoate, perfluorooctanoate, amines, octenidine
dihydrochloride, alkyltrimethylammonium salts, cetyl
trimethylammonium bromide, cetyl trimethylammonium chloride,
cetylpyridinium chloride, benzalkonium chloride, benzethonium
chloride, 5-Bromo-5-nitro-1,3-dioxane, dimethyldioctadecylammonium
chloride, cetrimonium bromide, dioctadecyldimethylammonium bromide,
sultaines, cocamidopropyl hydroxysultaine, betaines, cocamidopropyl
betaine, phospholipids phosphatidylserine,
phosphatidylethanolamine, phosphatidylcholine, sphingomyelins,
fatty alcohols, cetyl alcohol, stearyl alcohol, cetostearyl
alcohol, stearyl alcohols. oleyl alcohol, polyoxyethylene glycol
alkyl ethers, octaethylene glycol monododecyl ether, pentaethylene
glycol monododecyl ether, polyoxypropylene glycol alkyl ethers,
glucoside alkyl ethers, polyoxyethylene glycol octylphenol ethers,
polyoxyethylene glycol alkylphenol ethers, glycerol alkyl esters,
polyoxyethylene glycol sorbitan alkyl esters, sorbitan alkyl
esters, cocamide MEA, cocamide DEA, dodecyldimethylamine oxide,
polyethoxylated tallow amine, and block copolymers of polyethylene
glycol and polypropylene glycol.
[0087] In certain embodiments, the wetting agent is a surfactant.
In some embodiments, the surfactant is selected from a group
including multifunctional agents based on acetylenic chemistry,
ethoxylated low-foam agents, siloxane-based surfactants, and
nonionic superwetting and coalescing surfactants. For example,
suitable surfactants include Surfynol 61 (multifunctional agent
based on acetylenic chemistry), Surfynol 440 (ethoxylated low-foam
wetting agent), Dynol 980 (siloxane-based surfactant), Dynol 360
(nonionic superwetting and coalescing surfactant), and similar
agents, all commercially available from Air Products and Chemicals,
Inc. (Allentown, Pa.).
[0088] In certain embodiments, the wetting agent is a surfactant
having a boiling point of 200.degree. C. or lower. In some
embodiments, the surfactant has a boiling point of 150.degree. C.
or lower. In some embodiments, the surfactant has a boiling point
of 110.degree. C. or lower. For example, the surfactant may be a
multifunctional agent based on acetylenic chemistry or an
ethoxylated low-foam agent. Without intending to be bound by a
particular, it is believed that use of a surfactant having such a
low boiling or decomposition temperature encourages evaporation and
thereby loss of wetting functionality during the board drying
process. In particular, high Cobb (surface water absorption) was
found in certain boards due to residual surfactants left in the
glass mat on board surface, which promoted wetting again and
increased surface water absorption. Even at higher board drying
temperatures, the temperature was still not high enough to
evaporate off all surfactants, and Cobb remained high. Therefore
the low boiling point surfactants advantageously demonstrate
increased surface evaporation and resulting low Cobb (water
absorption) properties.
[0089] In certain embodiments, the wetting agent is deposited onto
the first fiberglass mat in an amount of at least about 0.01
lb/1,000 ft.sup.2, such as from about 0.01 lb/1,000 ft.sup.2 to
about 1 lb/1,000 ft.sup.2, from about 0.01 lb/1,000 ft.sup.2 to
about 5 lb/1,000 ft.sup.2, or from about 0.01 lb/1,000 ft.sup.2 to
about 10 lb/1,000 ft.sup.2.
[0090] In some embodiments, the aqueous liquid containing the
wetting agent is free of any polymer or inorganic binders. In
particular, it has been found that an aqueous liquid containing a
wetting agent, even absent a binder, provides the desired improved
gypsum slurry penetration. In other embodiments, the aqueous liquid
contains a binder in addition to the wetting agent. For example,
the binder may be any suitable binder as discussed above with
reference to gypsum layer additives. In certain embodiments, the
binder is a polymer or inorganic binder, such as a latex binder
that is free of filler.
[0091] In certain embodiments, depositing the aqueous liquid onto
the fibrous mat includes spraying, curtain coating, rolling,
brushing, knife coating, or wire rod application of the coating
onto the first surface of the mat. In certain embodiments, the
aqueous liquid is deposited onto a fibrous surface of the
fiberglass mat by a roll coater, knife coater, curtain coater,
wire-rod coater, spraying, or combinations thereof. In some
embodiments, the method includes vacuuming excess aqueous liquid
from the first fiberglass mat after depositing the aqueous binder
coating thereon.
[0092] Continuous Barrier Coating
[0093] In certain embodiments, the external surface of the fibrous
mat is coated with a continuous barrier coating that penetrates a
portion of the first fiberglass mat, to define the remaining
portion of the first fiberglass mat that gypsum crystals of the
gypsum core penetrate.
[0094] In certain embodiments, the first and/or second fibrous mats
are already coated upon contacting the gypsum (or other panel core)
slurry. In some embodiments, the methods include applying the
continuous coating to the first and/or second fibrous mat, either
before or after contacting the mats with the panel core slurry. In
certain embodiments, applying the barrier coating includes spray
coating, ribbon coating, or direct roll coating. In some
embodiments, the barrier coating is applied to each of the first
and/or second fibrous mats in an amount from about 1 pound to about
9 pounds, per 100 ft.sup.2. For example, the barrier coating may be
applied to the first and/or second fibrous mat in an amount from
about 2 pounds to about 8 pounds, per 100 ft.sup.2. In other
embodiments, coated fibrous mats may be obtained in a
pre-fabricated form.
[0095] Gypsum Core
[0096] In certain embodiments, the gypsum core includes multiple
layers that are sequentially applied to the fiberglass mat, and
allowed to set either sequentially or simultaneously. In other
embodiments, the gypsum core includes a single layer. In some
embodiments, a second fiberglass mat may be deposited onto a
surface of the final gypsum slurry layer (or the sole gypsum slurry
layer), to form a dual mat-faced gypsum panel. For example, the
second fiberglass mat may include a barrier coating on its surface
that penetrates a portion of the mat. The gypsum slurry or multiple
layers thereof may be deposited on the fiberglass mat by any
suitable means, such as roll coating.
[0097] In certain embodiments, depositing the gypsum slurry
includes depositing a first gypsum slurry having a wet density of
from about 88 pcf to about 98 pcf onto the surface of a fiberglass
mat, the first gypsum slurry. In certain embodiments, the first
gypsum slurry has a wet density of from about 93 pcf to about 96
pcf. In some embodiments, the gypsum core includes at least three
gypsum layers, with the outermost gypsum layers of the gypsum core
(i.e., the layers that form an interface with the fiberglass mats)
being slate coat layers. In certain embodiments, both outermost
layers have a relatively high density or are otherwise chemically
altered for enhanced penetration. Thus, a third gypsum slurry may
have a wet density of from about 88 pcf to about 98 pcf, or from
about 93 pcf to about 96 pcf.
[0098] In certain embodiments, depositing the gypsum slurry
includes depositing a first gypsum slurry containing a wetting
agent, as described in more detail below. The first gypsum slurry
may be the first of multiple gypsum layers deposited to form the
gypsum core (i.e., a slate coat layer), or the first gypsum slurry
may be the sole gypsum layer deposited to form the gypsum core. The
first gypsum slurry (or both of the outermost gypsum slurries) may
contain a wetting agent in an amount effective to reduce a surface
tension of the first gypsum slurry to 65 dyne/cm or less, measured
on the aqueous liquid after solid ingredients are filtered out. In
certain embodiments, the first gypsum slurry contains a wetting
agent in an amount effective to reduce a surface tension of the
first gypsum slurry to 60 dyne/cm or less. In certain embodiments,
the first gypsum slurry contains a wetting agent in an amount
effective to reduce a surface tension of the first gypsum slurry to
55 dyne/cm or less. In certain embodiments, the first gypsum slurry
includes a wetting agent in an amount effective to reduce a surface
tension of the first gypsum slurry to from about 40 dyne/cm to
about 65 dyne/cm. The reduced surface tension of aqueous liquid in
the gypsum slurry enhances the slurry penetration into the glass
mat, in reference to the pure water surface tension of 72 dyne/cm
at 25.degree. C. In certain embodiments, the first gypsum slurry
(or each of the outermost gypsum slurry layers) is deposited in an
amount of from about 5 percent to about 20 percent, by weight, of
the gypsum core.
[0099] In certain embodiments, the wetting agent is selected from a
group consisting of surfactants, superplasticisers, dispersants,
agents containing surfactants, agents containing superplasticisers,
agents containing dispersants, and combinations thereof. For
example, the gypsum slurry or layer(s) may include wax, wax
emulsions and co-emulsions, silicone, siloxane, or a combination
thereof. For example, suitable superplasticisers include Melflux
2651 F and 4930F, commercially available from BASF Corporation.
[0100] In certain embodiments, the wetting agent is a surfactant
having a boiling point of 200.degree. C. or lower. In some
embodiments, the surfactant has a boiling point of 150.degree. C.
or lower. In some embodiments, the surfactant has a boiling point
of 110.degree. C. or lower. For example, the surfactant may be a
multifunctional agent based on acetylenic chemistry or an
ethoxylated low-foam agent. Without intending to be bound by a
particular, it is believed that use of a surfactant having such a
low boiling or decomposition temperature encourages evaporation an
thereby loss of wetting functionality during the board drying
process. In particular, high Cobb (surface water absorption) was
found in certain boards due to residual surfactants left in the
glass mat on board surface, which promoted wetting again and
increased surface water absorption. Even at higher board drying
temperatures, the temperature was still not high enough to
evaporate off all surfactants, and Cobb remained high. Therefore
the low boiling point surfactants advantageously demonstrate
increased surface evaporation and resulting low Cobb (water
absorption) properties. In certain embodiments, there is no
residual wetting agent present in the set gypsum core.
[0101] In certain embodiments, the surfactant is present in the
first gypsum slurry in an amount of about 0.01 percent to about 1
percent, by weight. In certain embodiments, the surfactant is
present in the first gypsum slurry in an amount of about 0.01
percent to about 0.5 percent, by weight. In some embodiments, the
surfactant is present in the first gypsum slurry in an amount of
about 0.05 percent to about 0.2 percent, by weight.
[0102] Suitable surfactants and other wetting agents may be
selected from non-ionic, anionic, cationic, or zwitterionic
compounds, such as alkyl sulfates, ammonium lauryl sulfate, sodium
lauryl sulfate, alkyl-ether sulfates, sodium laureth sulfate,
sodium myreth sulfate, docusates, dioctyl sodium sulfosuccinate,
perfluorooctanesulfonate, perfluorobutanesulfonate, linear
alkylbenzene sulfonates, alkyl-aryl ether phosphates, alkyl ether
phosphate, alkyl carboxylates, sodium stearate, sodium lauroyl
sarcosinate, carboxylate-based fluorosurfactants,
perfluorononanoate, perfluorooctanoate, amines, octenidine
dihydrochloride, alkyltrimethylammonium salts, cetyl
trimethylammonium bromide, cetyl trimethylammonium chloride,
cetylpyridinium chloride, benzalkonium chloride, benzethonium
chloride, 5-Bromo-5-nitro-1,3-dioxane, dimethyldioctadecylammonium
chloride, cetrimonium bromide, dioctadecyldimethylammonium bromide,
sultaines, cocamidopropyl hydroxysultaine, betaines, cocamidopropyl
betaine, phospholipids phosphatidylserine,
phosphatidylethanolamine, phosphatidylcholine, sphingomyelins,
fatty alcohols, cetyl alcohol, stearyl alcohol, cetostearyl
alcohol, stearyl alcohols. oleyl alcohol, polyoxyethylene glycol
alkyl ethers, octaethylene glycol monododecyl ether, pentaethylene
glycol monododecyl ether, polyoxypropylene glycol alkyl ethers,
glucoside alkyl ethers, polyoxyethylene glycol octylphenol ethers,
polyoxyethylene glycol alkylphenol ethers, glycerol alkyl esters,
polyoxyethylene glycol sorbitan alkyl esters, sorbitan alkyl
esters, cocamide MEA, cocamide DEA, dodecyldimethylamine oxide,
polyethoxylated tallow amine, and block copolymers of polyethylene
glycol and polypropylene glycol. For example, suitable surfactants
include Surfynol 61, commercially available from Air Products and
Chemicals, Inc. (Allentown, Pa.).
[0103] In certain embodiments, the gypsum slurry (or one or more
layers thereof) includes a hydrophobic additive. For example, the
gypsum slurry or layer(s) may include wax, wax emulsions and
co-emulsions, silicone, siloxane, silanes, or any combination
thereof.
[0104] In certain embodiments, the first gypsum slurry includes,
alternatively to or in addition to the surfactant, an aqueous
polymer or inorganic binder to enhance penetration of the slurry
into the mat. In certain embodiments, the first gypsum slurry
includes the binder in an amount effective to provide from about
0.5 lb/1000 ft.sup.2 to about 50 lb/1000 ft.sup.2 binder in the set
gypsum layer. In one embodiment, the first gypsum slurry includes
the binder in an amount effective to provide from about 0.5 lb/1000
ft.sup.2 to about 15 lb/1000 ft.sup.2 binder in the set gypsum
layer. For example, the binder may be a suitable latex binder, such
as a hydrophobic modified acrylic latex binder. In one embodiment,
the latex binder is one with low surface tension, such as ENCOR
300, commercially available from Arkema (France).
[0105] For example, the binder may be styrene-butadiene-rubber
(SBR), styrene-butadiene-styrene (SBS), ethylene-vinyl-chloride
(EVCl), poly-vinylidene-chloride (PVdCl) and poly(vinylidene)
copolymers, modified poly-vinyl-chloride (PVC), poly-vinyl-alcohol
(PVOH), ethylene-vinyl-acetate (EVA), poly-vinyl-acetate (PVA) and
polymers and copolymers containing units of acrylic acid,
methacrylic acid, their esters and derivatives thereof
(acrylic-type polymers), such as styrene-acrylate copolymers. In
one embodiment, the binder is a hydrophobic, UV resistant polymer
latex adhesive. For example, the hydrophobic, UV resistant polymer
latex binder adhesive may be based on a (meth)acrylate polymer
latex, wherein the (meth)acrylate polymer is a lower alkyl ester,
such as a methyl, ethyl or butyl ester, of acrylic and/or
methacrylic acids, and copolymers of such esters with minor amounts
of other ethylenically unsaturated copolymerizable monomers (such
as styrene) which are known to the art to be suitable in the
preparation of UV resistant (meth)acrylic polymer latexes. In
certain embodiments, the binder coating is free of filler.
[0106] In certain embodiments, the gypsum slurry (or one or more
layers thereof) is substantially free of foam, honeycomb, excess
water, and micelle formations. As used herein, the term
"substantially free" refers to the slurry containing lower than an
amount of these materials that would materially affect the
performance of the panel. That is, these materials are not present
in the slurry in an amount that would result in the formation of
pathways for liquid water in the glass mat of a set panel, when
under pressure.
[0107] In some embodiments, the gypsum core includes at least three
gypsum layers, with the outermost gypsum layers of the gypsum core
(i.e., the layers that form an interface with the fiberglass mats).
In certain embodiments, both outermost layers are chemically
altered for enhanced penetration.
[0108] Mechanical Vibration of Panels
[0109] In some embodiments, the method also includes mechanically
vibrating at least the first fiberglass mat having the first gypsum
slurry deposited thereon to effect penetration of the gypsum slurry
into the remaining fibrous portion of the first fiberglass mat. In
certain embodiments, the method includes passing at least the first
fiberglass mat having the first gypsum slurry deposited thereon
over a vibration table. For example, a fiberglass mat having only
one layer of gypsum slurry deposited thereon (such as the slate
coat), or a fiberglass mat having multiple gypsum slurry layers,
and optionally a second fiberglass mat opposite the first
fiberglass mat, may be passed over a vibration table. In certain
embodiments, the first fiberglass mat and gypsum slurry are passed
over the vibration table prior to the panel being passed through a
forming plate. In certain embodiments, the vibration table includes
at least one vibrating plate configured to display a mean vibration
of from about 5 in/s to about 10 in/s. In certain embodiments, the
vibration table includes at least one vibrating plate configured to
vibrate at a frequency of from about 32 Hz to about 20 kHz. In some
embodiments, the fiberglass mat and gypsum are passed over two
sequential vibrating plates. It has been found that compared to
traditional rolls having nubs thereon, the vibration tables achieve
superior gypsum slurry penetration of the fiberglass mat.
[0110] Other Process Parameters and Properties
[0111] In certain embodiments, the panel core slurry (or layers
thereof) may be deposited on the non-coated side of a horizontally
oriented moving web of pre-coated fibrous mat. A second coated or
uncoated fibrous mat may be deposited onto the surface of the panel
core slurry opposite the first coated fibrous mat, e.g., a
non-coated surface of the second coated fibrous mat contacts the
panel core slurry. In some embodiments, a moving web of a
pre-coated or uncoated nonwoven fibrous mat may be placed on the
upper free surface of the aqueous panel core slurry. Thus, the
panel core material may be sandwiched between two fibrous mats, one
or both having a barrier coating. In certain embodiments, allowing
the panel core material and/or continuous barrier coating to set
includes curing, drying, such as in an oven or by another suitable
drying mechanism, or allowing the material(s) to set at room
temperature (i.e., to self-harden).
[0112] Gypsum panels disclosed herein advantageously display
improved core-to-mat adhesion and gypsum penetration into the mat,
leading to improved surface water resistance and weathering
performance.
[0113] Methods of constructing a building sheathing system, as
shown in FIG. 3, are also provided herein, including installing at
least two gypsum panels 300 having an interface therebetween, and
applying a seaming component 320 at the interface between the at
least two of the gypsum panels 300. Gypsum panels used in these
methods may have any of the features, properties, or combinations
of features and/or properties, described herein. Sheathing systems
constructed by these methods may have any of the features,
properties, or combinations or features and/or properties,
described herein. The seaming component may be any suitable seaming
component as described herein.
[0114] Thus, the gypsum sheathing panels and building sheathing
systems disclosed herein display water-resistive and air-barrier
properties that were previously achieved in gypsum panels only
through attaching separate water-resistive air barriers (e.g.,
mechanically attached flexible sheet, self-adhered sheets,
fluid-applied membranes, spray foams) thereto. Because gypsum
panels display fire resistance properties, these panels and systems
provide advantages over wood-based (e.g., OSB) panels.
[0115] In these gypsum panels and sheathing systems, air pockets or
voids are substantially eliminated, so that the panels display the
desired water resistive barrier and air barrier properties
independent of externally applied barrier products. These improved
sheathing panels may be combined with seaming components (i.e.,
components that treat the joints, or seams, between panels) to
greatly reduce the cost, time, and complexity of installation of a
water-resistive air barrier that provides the desired resistance to
bulk water without affecting the water vapor transmission rate of
the panel. Accordingly, the disclosed system advantageously
eliminates the need for applying further materials to a gypsum
panel (e.g., either a membrane or liquid/foam material) to achieve
water-resistive air barrier properties, when the seams are treated,
and also provides fire resistance.
[0116] While the disclosure has been described with reference to a
number of embodiments, it will be understood by those skilled in
the art that the invention is not limited to such disclosed
embodiments. Rather, the invention can be modified to incorporate
any number of variations, alterations, substitutions, or equivalent
arrangements not described herein, but which are commensurate with
the spirit and scope of the invention. Additionally, while various
embodiments of the invention have been described, it is to be
understood that aspects of the invention may include only some of
the described embodiments. Accordingly, the invention is not to be
seen as limited by the foregoing description, but is only limited
by the scope of the appended claims.
* * * * *